The present invention relates to a waterproofing apparatus for a terminal connecting portion of a sheathed wire for providing waterproofing by resin molding.
In general, in the case of a sheathed wire, a tip portion of its sheath is stripped off to expose a conductor, and the conductor is connected to an electric component or device through a terminal fitting crimped onto the bared conductor by caulking or the like. If the bared conductor after crimping is left as it is, trouble can occur in which water can be transmitted to and permeate the sheathed wire, and can possibly enter the interior of the sheathed wire through the capillary phenomenon. To prevent this, the terminal connecting portion including the bare conductor is protected by various covering members to provide waterproofing.
For example, a terminal fitting for grounding disclosed in Japanese Patent Publication No. 10-289745A provides waterproofing by covering the bare conductor of the terminal connecting portion with a heat-shrinkable tube and by heating and fusing the tube. In addition, as in the case of a connection plate for a battery holder disclosed in Japanese Patent Publication No. 11-120986A, a technology is also known in which, in the wiring for power supply cells of an electric vehicle, a terminal connecting portion with a terminal fitting crimped to a bare conductor is covered and protected by a molding resin to provide waterproofing.
FIGS. 4A and 4B are front cross-sectional views schematically illustrating states persisting before and after mold releasing is effected after allowing a molding resin to cool and cure subsequent to its injection in a mold which makes up essential portions of a resin-molding waterproofing apparatus, so as to conceptually explain the aforementioned latter related resin-molding waterproofing apparatus.
In the case of a bare wire 1 serving as a workpiece to be molded, a terminal connecting portion is formed in advance in preparation for molding by exposing a conductor 2 with a tip portion of its sheath stripped off and by crimping a caulking portion 3 of a terminal fitting onto the bared conductor 2 by caulking or the like.
A mold 4 is comprised of an upper mold 5 and a lower mold 6, and molding portions 7 and 8 are respectively provided inside the upper and lower molds 5 and 6 as molding cavities in which the aforementioned terminal connecting portion is set. A molten molding resin 9 is poured through a runner channel of an injection gate, and is fused onto the terminal connecting portion in such a manner as to cover substantially the entire portion of the terminal connecting portion. After the cooling and curing of the molding resin 9, the upper and lower molds 5 and 6 are relatively operated to release from the mold the terminal connecting portion for which waterproofing by molding has been completed, as shown in FIG. 4B.
In the related resin-molding waterproofing apparatus shown in FIGS. 4A and 4B, the entire terminal connecting portion for which waterproofing has been completed by fusing the molding resin 9 onto it is lifted off together with the upper mold 2 during the mold releasing shown in FIG. 4B. To remove such a terminal connecting portion from the upper mold 2, an operator must look up at the terminal connecting portion from a lower direction and is therefore bound to assume an unnatural posture. In mass production, the physical burden increases, and has constituted a cause for lowering the efficiency in the molding operation.
Accordingly, an object of the invention is to provide a waterproofing apparatus for a terminal connecting portion of a sheathed wire which enhances the efficiency of the molding operation by making it possible to allow the terminal connecting portion after molding to be released from the mold in a satisfactory state when the terminal connecting portion formed with a terminal fitting crimped onto the conductor at the tip portion of the sheathed wire is provided with waterproofing by being molded and covered with a resin in the mold.
In order to achieve the above object, according to the present invention, there is provided an apparatus for waterproofing a terminal connecting portion of a sheathed wire, in which a terminal fitting and a bared conductor of the sheathed wire are connected with each other, by molding with resin, the apparatus comprising:
an upper mold having an inner space provided with a dome-like ceiling face, which defines an upper part of a molding cavity in which the terminal connecting portion of the sheathed wire is accommodated and molten resin is injected therein; and
a lower mold having an inner space provided with vertical side faces and a bottom face, which defines a lower part of the molding cavity.
Preferably, the dome-like ceiling face of the upper mold has a curvature so selected as to be coincident with a curvature of an outer face of the terminal fitting.
By virtue of the above-described arrangement, the molding portion of the upper mold provided on the mating surface of the lower mold is provided with a gradient or a curvature for facilitating mold releasing. A molding resin in a molten state is injected and poured into the cavities of the molding portions of the upper and lower molds so as to cover the terminal connecting portion. When effecting mold releasing after the cooling and curing of the molding resin, the molding portion of the upper mold can be easily released from the terminal connecting portion subjected to covering and molding, and the terminal connecting portion remains in the molding portion of the lower mold. The terminal connecting portion subjected to covering and molding which remained in the lower mold can be removed with a natural operating posture.